Venting means for chambers of rubber mixers or the like



June 8, 1954 D. w, acLEoD 2,680,264

VENTING MEANS FOR CHAMBERS OF RUBBER MIXERS OR THE LIKE Filed March 17, l951 3 Sheets-$heet l INVENTOR ATTORNEYS D- w. M LEOD 2,680,264 VENTING MEANS FOR CHAMBERS OF RUBBER MIXERS OR THE LIKE June 8, 1954 3 Sheets-Sheet 2 Filed March 17, 1951 29 A W 7 BY I W as INVENTOR My ATT June 8, 1954 3, w MaOLEOD 2,680,264

VENTING MEANS FOR CHAMBERS OF RUBBER MIXERS OR THE LIKE Filed March 17, 1951 5 Sheets-Sheet 5 'zz \r I 50A 4!- INVENTOR jp yh hf )fac M Wm Patented June 8, 1954 UNITED STATES PATENT OFFICE VENTING MEANS FOR CHAMBERS OF I RUBBER MIXERS OR THE LIKE Douglas W. MacLeod, Ansonia, Conn.,

assignor Application March 17, 1951, Serial No. 216,169

'7 Claims. i

This invention relates to venting means for chambers of mixers or masticators, and particularly to a device of the kind for venting or relieving the pressure in the chamber of a rubber mixer or masticator, such, for example, as the usual Banbury type machine. It will be understood, however, that the invention in its broader aspects is applicable to other types of machines.

In the mixing or masticating of plastic materials, and more especially in the treating of rubber in a mixer of the type described above, considerable pressure is developed in the chamber during the mixing operation. This pressure becomes so great that it is desirable to relieve the pressure by venting the chamber. A batch of rubber which is being processed is often mixed with other materials, some of which are In powder form, and it is, of course, desirable to retain all of the material within the chamber. Therefore, the venting must be accomplished in such a manner that while gas is permitted to escape in order to relieve the pressure, the constituents of the charge or batch will be retained within the chamber.

For this reason it is desirable that the venting openings be relatively small or narrow, and such openings should be prevented from becoming clogged by the material of the batch which is carried around by the blades of the rotors. According to the present disclosure, I have provided venting means for the chamber of a mixer of this kind in the form of a filter which consists of a plurality of parallel plates set closely together so that narrow openings are provided between adjacent plates, which openings lead r from the chamber and allow the gas to vent therefrom.

Moreover, the ends of these plates, which are in the chamber and which provide between them the narrow openings, are arranged closely adjacent to the path of the tips of the blades upon the rotor in that part of the chamber, leaving a relatively small clearance between the rotor blades and the inner edges of the plates so that the latter will be wiped on and prevented from clogging by the movement of the blades in the chamber. In this manner the openings can be made relatively small so that gas will be permitted to escape from the chamber while the elements of the charge will be retained therein and at the same time the filter openings will not become clogged so as to be rendered inoperative for the purpose for which they are provided.

As illustrated, the chamber ofthe mixing de vice is provided with a charging stack which communicates with the chamber and which is closed by a plunger and a weight. The filter is provided in this weight so as to permit the gas to escape from the chamber through the weight and up the charging stack.

Also, as illustrated in the drawing the weight is secured loosely to the plunger so that it is permitted a certain amount of play or rocking movement from side to side, and while at its lower end the plunger fits the charging stack fairly closely, the side walls of the weight may be tapered upwardly to some extent to permit the escape of gas from the chamber. The lower end of the plunger may be V shaped in form to provide a keel efiect so that upon rotation of the rotors in the chamber, the impact or pressure of the charge upon the lower end of the weight will tend to cause the latter to rock or oscillate and serve to vent the chamber to some extent. This provision for a rocking or oscillating movement of the weight may be used with or without the filter device referred to above, and the latter may also be used independently of the rockable weight.

One object of the invention is to provide means for venting the gases from a rubber mixer or like device. I 7

Another object of the invention is to provide a venting means for the chamber of a rubber mixer or like machine which venting means comprises. a filter device presenting restricted openings to permit gas to escape from the chamber.

A still further object of the invention is to provide a rubber mixing machine having a charging stack and a weight closing the communication between the stack and the chamber with a venting means comprising a filter device arranged in the weight or closure member whereby the gas vented from the chamber will be vented into the charging stack.

Still another object of the invention is to provide a venting means for a rubber mixer or the like, which venting means comprises a filter member consisting of a plurality of plates presenting narrow openings between adjacent plates to permit escape of gas from the chamber, and

to position these plates relatively to the rotor so that the action of the rotor will prevent the restricted openings between the plates from becoming clogged.

Still another object of the invention is to provide a rubber mixer having a chamber and a charging stack communicating with the chamber with a weight or closure member for the 3 stack, the weight being so proportioned relative- 1y to the stack and so supported therein that it will rock from side to side during the operation of the device, and therefore, permit escape of gas from the chamber.

To these and other ends the invention consists in the novel features and combinations of parts to be hereinafter described and claimed.

In the accompanying drawings:

Fig. 1 is a central sectional view of a rubber mixer of the Banbury type embodying my invention;

Fig. 2 is a sectional view on line 2-2 of Fig. 1 showing the weight or closure member;

Fig. 3 is a sectional view on line 3-3 of Fig. 2;

Figs. 4 and 5 are sectional views on lines 4-4 and 5-5 respectively of Fig. 3;

Fig. 6 is a perspective view of one of the plates of the filter member of the device;

Fig. 7 is an enlarged sectional view of a portion of the filter member; and

Fig. 8 is an elevational view of the inner face of one of the plates of the weight.

To illustrate a preferred embodiment of my invention, I have shown in the drawings a rubber mixer of the Banbury type which comprises a chamber H! of the double cylindrical type, having therein bladed rotors ll and I2, these rotors operating in opposite directions, as shown by the arrows thereon so that when the blades are at the upper portions of the chamber they move toward the center of the chamber.

The chamber is provided with a charging stack l3 of generally rectangular form in cross section and is charged through the hopper 14. At its lower end the stack communicates with the chamber, and a closure member is provided for the stack in the form of the weight l5 which is carried at the lower end of the plunger $6. The plunger may be raised by any suitable means such as the piston I! to raise the weight to a sufficient height to permit the charging of the chamber through the stack.

The construction of the weight is shown more particularly in Figs. 2 and 3 where it will be seen that it is provided with a cylindrical portion H! which receives theplunger 15, the latter being secured to the weight by means of a pin 19 passing loosely through an opening 20 in the piston, which opening is somewhat larger than the pin [9, as shown in Fig. 1. Thus, the weight is loosely connected to the plunger 16 and will be permitted a rocking movement from side to side in the stack.

The lower portion of the piston comprises a V-shaped or keel-shaped bottom member 2| which projects slightly into the chamber when the weight is at its lowermost portion, shown in Fig. 1, so as to lie in proximity to the tips upon the blades of the rotors H and I2. The weight also comprises end members 22, a side member 23 connecting the end members, and a diagonal strut member 24, all of which may be secured together as by welding to form a rigid structure.

As will be seen from Figs. 1 and 3, the end members 22 are tapered slightly toward their upper edges so that they are narrower at their upper than at their lower edges, and thus clearance is given to permit the side to side rocking or oscillating movement heretofore referred to. It will be understood that when the charge is propelled about the chamber by the rotors, the impact of the charge against the lower faces of the keel-shaped member 2| will cause the weight to rock in the stack.

While this rocking movement of the weight will permit the escape of gas to some extent from the stack, I have also illustrated independent means for venting the stack comprising a filter member carried by the weight which will now be described.

As shown in Fig. 8, each of the end plates is provided with diagonal grooves or recesses 26 and 21, and in these grooves are fitted the edges of plates 28 and 29 which, as will be explained, support the filter member. A third plate 30 (Fig. 4) is disposed across the rear edges of the plates 28 and 29, and may be welded thereto, as shown at 31. These three plates 28, 29 and 30 together with the end plate 22 form a rectangular frame or box for the bars or plates of the filter member.

As shown in Fig. 5, each of the end plates is provided with a shoulder 32 extending partway across the same, and the plate 30 is provided with a similar shoulder 33, and above these shoulders these plates are provided with recesses 34 and 35 respectively. The filter member proper is comprised of a plurality of parallel bars or plates, the form of which is shown in Figs. 6 and 7. It will be noted that, as shown in Fig. 7, the body portions 38 of these bars taper upwardly in width so that they will be set closer together at their lower edges than at their upper edges, providing narrow slots 3! therebetween, which slots face and are in communication with the chamber. Adjacent the central portions and adjacent the ends of the bars 36 are thickened portions 38 which, when the bars are assembled, contact each other to space apart the body portions 36. At the ends of the bars, the portions 38 are cut away to provide downwardly facing shoulders 39 and, as will be seen from Fig. 5, when the bars are assembled between the plates 22 and 30, the shoulders 39 rest upon the shoulders 32 and 33. i'he bars or plates 36 may be slipped into place from above, as shown in Fig. 5, between the plates 22 and 3G, a sufficient number being put into place so that the rectangular space provided between the end wall 22 and the plates 28, 29 and 38 has been filled. The thickened portions 38 of one bar will, as stated, contact the adjacent bar and hold them in spaced relation providing the restricted openings 31 therebetween.

In order to hold the bars in place L-shaped members ll and 42 may be placed above the filter bars 36 with the horizontal portions of these plates extending into the recesses 34 and 35. These plates are connected together by a link 43 of oblong shape in cross section for the greater part of its length, the end of this link being rotatably received in the member 42, and at its other end being threaded, as shown at 44, and threadedly received in the member 4!. It will be understood that by turning the member 33, the member 4% may be drawn inwardly until the plates M and d2 are sufficiently close together to he slipped into position above the bars 36. Thereafter the link 43 may be turned in the proper direction to separate the members 4! and 42 and move the lower ends of these members into the recesses 34 and 35, thus clamping the bars 36 in place.

As shown more especially in Fig. 2, one of these filter members is provided at each end of the weight, the two facing the same direction so that they will face toward one of the rotors. It will also be apparent from Figs. 1 and 5 that the lower ends of the bars 35 extend within close proximity to the tips of the plates of the rotor at one side of the chamber, there being a clearance of approximately 4 to of an inch between the tip of the blade and the inner surfaces of the bars. The blades, therefore, at each revolution wipe off the bars and prevent the openings from becoming clogged, and, therefore, becoming inoperative to vent gas from the chamber.

While I have shown and described a preferred embodiment of my invention, it will be understood that it is not to be limited to all of the details shown, but is capable of modification and variation within the spirit of the invention and within the scope of the claims.

What I claim is:

1. A mixer for plastic materials comprising a chamber, rotor means within the chamber to act on the charge therein, said chamber having a charging opening, a closure member for said opening, said closure member having an opening therein, bars extending across said opening and spacing means between said bars to provide narrow venting slots between the bars.

2. A mixer for plastic materials comprising a chamber, rotor means within the chamber to act on the charge therein, said chamber having a charging opening, a closure member for said opening, said closure member having an opening therein, spaced bars extending across said opening .to provide relatively narrow slots between the bars, and the inner edges of the bars being disposed adjacent the path of the rotor to be cleaned thereby.

3. A mixer for plastic materials comprising a chamber, rotor means within the chamber to act on the charge therein, a charging stack leading into the chamber, a weight in said stack to close the chamber, said weight being provided with restricted openings at its lower portion to permit escape of gas from the chamber, said weight being tapered upwardly from its lower end to permit it to rock within the stack, and a plunger to which the weight is loosely connected.

4. A mixer for plastic materials comprising a chamber, rotor means within the chamber to act on the charge therein, a charging stack leading into the chamber, a weight in said stack to close the chamber, said weight being provided with restricted openings at its lower portion to permit escape of gas from the chamber, said weight being tapered upwardly from its lower end to permit it to rock within the stack and being provided with a keel-shaped portion at its lower face exposed to the material within the chamber, and a plunger to which the weight is loosely connected.

5. A mixer for-plastic materials comprising a chamber, rotor means within the chamber to act on the charge therein, said chamber having a charging opening, a closure member for said opening, said closure member having an opening therein, spaced bars extending across said opening to provide narrow venting slots, and said bars having projections thereon to contact adjacent bars'to hold them in spaced-apart relation.

6. A mixer for plastic materials comprising a chamber, rotor means within the chamber to act on the charge therein, said chamber having a charging opening, a closure member for said opening, said closure member being provided with spaced outwardly facing shoulders, one upon each side of an opening therein, bars extending across said opening and resting upon said shoulders, means holding said bars in spaced relation to provide restricted openings therebetween, and clamping means for locking said bars in place.

7. A mixer for plastic materials comprising a chamber, rotor means within the chamber to act on the charge therein, a charging stack leading into the chamber, a weight in said stack to close the opening of the stack into the chamber, the lower portion of said weight snugly fitting said stack, said weight being reduced in size at its upper portion to permit rocking movement of the weight in the stack, and a plunger to which said weight is loosely connected.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,523,387 Banbury Jan. 20, 1925 1,689,990 Banbury Oct. 30, 1928 1,905,755 Schnuck et al Apr. 25, 1933 2,266,831 Tegarty Dec. 23, 1941 2,351,706 Robinson June 20, 1944 2,442,368 Maynard June 1, 1948 

